Merck's 21-Valent Pneumococcal Vaccine Delivers More Positive Phase 3 Data in Advance of 6-17-2024 PDUFA Date

Merck today announced positive results from the phase 3 STRIDE-10 trial evaluating V116, the company’s investigational, 21-valent pneumococcal conjugate vaccine formulated specifically for adults aged 50 and older, at the34th European Society of Clinical Microbiology and Infectious Diseases (ESCMID Global) in Barcelona, Spain.¹

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STRIDE 10, the most recent in the Merck phase 3 clinical trial program for the 21-valent vaccine, evaluated the immunogenicity, tolerability, and safety of a single dose of V116 compared to a single dose PPSV23 (pneumococcal vaccine, polyvalent [23-valent]) in 1484 adults aged 50 years and older who were naïve to a pneumococcal vaccine.

Immune responses to V116 were found noninferior to responses to PPSV23 at day 30 for the 12 pneumococcal serotypes common to both vaccines; results are based on measures of opsonophagocytic activity (OPA) geometric mean titers (GMTs), according to the Merck release.¹

Immune responses elicited by V116 were superior for the 9 serotypes included in V116 but not PPSV23, as measured by OPA GMT ratios at day 30, and superior for 8 of 9 serotypes unique to V116 compared to PPSV23, as measured by the proportions of participants with at least a 4-fold rise in immune responses.¹

“Even with the availability of current pneumococcal conjugate vaccines for adults, gaps in serotype coverage for invasive pneumococcal disease persist,” Eliav Barr, MD, senior vice president, head of global clinical development and chief medical officer, Merck Research Laboratories said in the Merck statement.¹ “These data add to the evidence supporting the potential for V116 to become an important new preventative option for adults, with results showing V116 elicited immune responses to the serotypes responsible for the majority of adult invasive pneumococcal disease.”¹

Merck also presented data at ESCMID Global from 4 European studies that investigated the health and economic burdens of invasive pneumococcal disease and nonbacteremic pneumococcal pneumonia that are attributable to serotypes in V116 and PCV20 among adults in France, Sweden, Spain, and the Netherlands.¹ When researchers compared V116 with PCV20, they found considerably higher health and economic burden associated with the V116 serotypes across the 4 studies. The difference, according to Merck, is driven by the 8 serotypes unique to V116 that are not included in any currently licensed pneumococcal vaccine. Together the results suggest a role for V116 in improving outcomes for both infections in the countries studied.¹

The new data augment previous positive phase 3 findings presented in March 2024 at the 13th Meeting of the International Society of Pneumonia and Pneumococcal Diseases (ISPPD) in Cape Town, South Africa.²

V116 is specifically formulated to address Streptococcus pneumoniae serotypes predominantly responsible for adult pneumococcal disease, including 8 serotypes not in any currently approved pneumococcal vaccine (15A, 15C, 16F, 23A, 23B, 24F, 31 and 35B), according to Merck. The 8 serotypes are responsible for approximately 30% of adult IPD, according to CDC data from 2018-2021 and for approximately 83% of IPD in individuals 65 years of age and older.¹

“Invasive pneumococcal disease and pneumococcal pneumonia can cause serious illness, especially in older adults and those with immunocompromising conditions,” Walter Orenstein, MD, professor emeritus of medicine, epidemiology, global health and pediatrics at Emory University and member of Merck’s Scientific Advisory Committee said in an ISPPD the announcement.² “These positive data demonstrate the potential for V116 to address an unmet need in adult pneumococcal disease prevention.”²

The US FDA granted V116 priority review in December 2023 with a PDUFA date of June 17, 2024.

1. Merck announces positive data on V116, an investigational, 21-valent pneumococcal conjugate vaccine specifically designed for adults. News release. Merck. April 20, 2024. Accessed April 29, 2024. https://www.merck.com/news/merck-announces-positive-data-for-v116-an-investigational-21-valent-pneumococcal-conjugate-vaccine-specifically-designed-for-adults/

2. Halsey G. Merck's 21-valent adult-specific pneumococcal vaccine accrues new phase 3 and real world data. Patient Care. March 19, 2024. https://www.patientcareonline.com/view/merck-s-21-valent-adult-specific-pneumococcal-vaccine-accrues-new-phase-3-and-real-world-data